Human Science

Human Science

Carl Sagan said that there were no other species on Earth that does science: “It is, so far, entirely a human invention, evolved by natural selection in the cerebral cortex for one simple reason: it works. It is not perfect. It can be misused. It is only a tool. But it is by far the best tool we have, self-correcting, ongoing, applicable to everything.”

The Human Science, to be really, one has two rules which can’t be bent:

First: there are no sacred truths; all assumptions must be critically examined; arguments from authority are worthless.

Second: whatever is inconsistent with the facts must be discarded or revised. Present global culture is a kind of arrogant newcomer. It arrives on the planetary stage following four and a half billion years of other acts, and after looking about for a few thousand years declares itself in possession of eternal truths. But in a world that is changing as fast as ours, this is a prescription for disaster.

In fact, we must understand the Cosmos as it. We must not confuse how it is with how we wish it to be.

The obvious is sometimes false; the unexpected is sometimes true.

No nation, no religion, no economic system, no body of knowledge, is likely to have all the answers for our survival.  There may appear new social systems that would work far better than any now in existence.

In the past, science and learning were the preserve of a privileged few. The vast population had not the vaguest notion of the great discoveries taking place near by. Discoveries in mechanics and steam technology were applied mainly to the perfection of weapons, the encouragement of superstition, the amusement of kings. The scientists didn’t grasp the potential of machines (with few exceptions). The great intellectual achievements of antiquity had few immediate practical applications. Science never captured the imagination of the multitude. There was no counterbalance to stagnation, to pessimism, to the most abject surrenders to mysticism.

When the mob came to burn the Alexandrian Library down, there was nobody to stop them. Here clearly were the seeds of the modern world of total ignorance on another level. Image : © Megan Jorgensen.

Black Holes

Black Holes

When the gravity is very high, nothing, not even light, can get out. Such a place is called a black hole.  It is called black because no light can escape from it, but we can’t know what effect causes the light trapped down there. Well, things may be attractively well-li on the inside.

Enigmatically indifferent to its surroundings, a black hole a kind of cosmic Cheshire cat. Indeed, when the gravity and density become sufficiently high, the black hole winks out and disappears from our universe. That is why it is called black: no light can escape from it.

However, even if a black hole is invisible from the outside, its gravitational presence is palpable. If, on an interstellar voyage, astronauts are not paying attention, they can find themselves drawn into this stellar corps irrevocably, their bodies stretched into a long, thin thread. But the matter accreting into a disk surrounding the black hole would be sight worth remembering, in the unlikely case that the crew survived the trip.

Black holes were first thought of by the English astronomer John Mitchell in 1783. But the idea seemed so bizarre that it was generally ignored until quite recently. Then, to the astonishment of many, evidence was actually found for the existence of black holes in space: the Earth’s atmosphere is opaque to X-rays.

To determine whether astronomical objects emit such short wavelengths of light, an X-ray telescope must be carried aloft. The first X-ray observatory was an admirably international effort, orbited by the United States from an Italian launch platform in the Indian Ocean off the coast of Kenya and named Uhuru, the Swajili word for “freedom”.

In 1971, Uhuru discovered a remarkably bright X-ray source in the constellation of Cygnus, the Swan, flickering on and off a thousand times a second. The source, called Cygnus X-1, must therefore be very small. Whatever the reason for the flicker, information on when to turn on and off can cross Cyg X-1, no faster than the speed of light, 300, 000 km/sec. Thus Cyg X-1 can be no larger than 300,000 km/sec X 1/10000 sec = 300 kilometers across. Something the size of an asteroid is a brilliant, blinking source of X-rays, visible over interstellar distances.

Cyg X-1, a mysterious brilliant, blinking source of X-rays, visible over interstellar distances. What does it hide from us? Image: © Megan Jorgensen.

Brain: Internal and External Worlds

The Internal and External Worlds of Our Brain

The brain is an organ, but it is not an isolated organ. It is connected in various ways with the other organs of the body. This vital fact about the brain and how it works is all too often overlooked, especially by people who like to think of the brain as something analogous to a computer.

In a nutshell, the brain is connected to two “worlds”: the world within us, the internal milieu of the body; and the world outside us, the external environment. In a profound sense, the principal task of the brain is to mediate this divide – to mediate between the vital requirements of the internal milieu of the body (the vegetative functions) and the ever-changing world around us, which is the source of everything our bodies need but is indifferent to those needs (with the exception of our parents – especially during childhood – and other loved ones, who for that very reason occupy a special place in the mental economy).

The vegetative nervous system performs the task of keeping the body alive from moment to moment, controlling heart rate, breathing, digestion, temperature, and so forth. To perform these functions, the body requires, and actually consumes, material from the outside world – principally food, water, and oxygen. It also requires a suitable ambient temperature, as the organs of the body can only function within a very narrow temperature range. The same applies to sexual needs – though sexual “consummation” is necessary for the survival of our species as a whole rather than of each one of us individually. In short, to maintain and sustain the visceral jellyfish that we all have inside us, the internal world of the body has to interact in an appropriate way with the external world around us and make the world meet its needs, and it is the brain that manages this difficult task. When the external world no longer meets our many needs (when the brain is no longer able to regulate the inner functions of our bodies, by virtue of its interactions with the external world), we die – of hunger, thirst, suffocation, heatstroke, or one of the many other hazards that constantly threaten the integrity of the internal world of the body.

This point is obvious, and clearly irrevocable. How, then, does the brain perform these vital functions? In a broad sense, to begin with, we can address a narrower question: How is the brain linked, anatomically and physiologically, with the inner and outer world of the body?

It is important to remember that the action system always operates in concert with the perceptual systems, the primary function of which is to guide action. Photo by Elena.

Perceiving and representing the external world

The brain is connected to the outside world in two main ways. The first is through the sensory apparatus (the organs of vision, hearing, etc.); the second is through the motor apparatus (the so-called musculoskeletal system). This is how we receive information from the world and how we act on the world.

The essential facts are that sensation is generated by specialized sensory receptors (in the eye, ear, etc.), that transform selected physical features of the environment into nerve impulses and send the resultant information to the brain. In the case of vision, cells in the retina send (most, but not all) visual information, via part of the thalamus, to the back of the occipital lobes. A similar arrangement applies to hearing, in which case (most, but not all) auditory information is transmitted (via a different part of the thalamus) to the superior surface of the temporal lobe. In the case of somatic sensation (touch, pain, etc.), the relevant information is sent from the surfaces and joints of the body to (mainly) the anterior part of the parietal lobe. Many people refer to somatic sensation as the sense of “touch”. In fact, touch is part of a group of different sensory modalities that transmit several types of information from the surfaces of the body, of which tactile sensation is only one. There is also vibration sense, temperature sense, pain sense, and muscle- and joint-position sense. Each of these could be regarded as a sense modality in its own right, in that each is served by a specific type of receptor and projects separately to the brain. However, all these sense modalities send information to a roughly similar location in the brain, in the parietal lobe, which forms the basis of the body schema, and they are therefore grouped together as “somatic sensation”.

It is important to be aware that the modality of somatic sensation carries only part of the information about the state of the body to the brain – that is, information about the external aspect of the body., the “musculoskeletal” part, which is in contact with the outer world. We need to know about pain and temperature in the outside world in order to act on it. Information about the internal world, relating to the viscera, is not conveyed by sensors such as those for touch, pain, and do forth.

The two remaining sensory modalities – taste and smell – are “chemical” in nature. Taste is closely connected to somatic sensation in the tongue and is represented mainly in the cortex of the insula. Smell is connected to a range of structures inside the temporal lobe, including some parts of the limbic system.

The internal world

Until very recently, there was far less investigation of neuropsychological matters pertaining to the second aspect of reality – the influence of the inner world of the body on our mental life.

The internal milieu refers to the world of respiration, digestion, blood pressure, temperature control, sexual reproduction, and the like. These organs are responsible for the body's survival and in most cases loss of their functions would mean a rapid end to the life of the organism.

Information travels up through the spinal cord (and in other ways) from the interior of the body. This information reaches, in the first instance, the hypothalamus – which is the controlling mechanism (or “head ganglion”) of the autonomic nervous system (the system that controls the self-regulation aspects of the body). The hypothalamus is intimately connected with the group of structures known as the limbic system. One could say (using the language employed above in relation to external perceptions and action) that the functions of the internal milieu are “projected” onto the hypothalamus. The hypothalamus relays this information to a range of other structures throughout the limbic system and rest of the brain. In this way, the prevailing state of the body is linked with concurrent objects in the external world, and these links (which are of crucial importance for survival) are committed to memory.

Alongside the “perceptual” aspect of this internally directed system, there is also a “motor” component. There are two classes of action performed by this system. One influences the visceral milieu itself (via secretory discharges, vasomotor changes, etc.) These influences are mediated by the autonomic nervous system. But the visceral brain influences external action too. External action is mediated by the motor systems already discussed above, but, unlike voluntary action, the visceral brain releases stereotyped motor patterns, executed under compulsive pressure. This is the basis of instinctual behaviors and the expression of the emotions. Unlike voluntary action, this type of motor activity is mediated primarily by the basal ganglia. However, information about the state of the internal milieu also reaches the prefrontal lobes – where it makes an important contribution to the calculations performed by the unit for the programming, regulation, and verification of action.

Over most of the last century, neuroscience studied interaction of the mind with the environment, and tremendous progress was made. Picture by Elena.

The Brain and the Inner World, Introduction to Basic Concepts. Mark Solms, Oliver Turnbull.

Physiological Principles

Physiological Principles that distinguish the outer and inner worlds of our brain

The outer and inner sources of information can be distinguished not only on anatomical grounds, but on physiological grounds as well. The basic physiological division is embodied in the distinction that some neuroscientists draw between “channel” and “state” functions – the terms introduced by Mesulam  in 1998. His terminology is fairly idiosyncratic, but it denotes a relatively conservative concept, the physiological foundations of which are widely accepted. Other neuroscientists distinguish between the “contents” and “level” of consciousness – but these terms are less serviceable as they refer specifically to consciousness and thereby exclude the possibility of unconscious mental  processes. Mesulam's distinction between the channel and state functions of the brain is perhaps roughly equivalent to the distinction that psychoanalysis draw between mental representations (“traditional traces”) and mental energies (“quotas of affect”).

Brain functions (principally, forebrain functions) dependant on information derived from the external world are primarily channel-dependent functions. This means that the information processed by these systems comes in discrete bits and is communicated via distinct and specific pathways. Information transmitted from a particular source within a channel-dependent system is not widely distributed to the brain as a whole but, rather, is targeted with great accuracy to other discrete regions. For example, when information arrives at a particular location on the retinae (say 30 degrees below the horizontal and 20 degrees left of the vertical meridian), it projects to a highly specific area of primary visual cortex which represents that precise location on the retinae (and therefore in the external visual field). The coral aspects of this information then project to specific color areas, as do the motion aspects, and so on. In each case, a limited number of neurons directly “speak to” a limited number of other neurons some distance away, while the vast bulk of the brain is completely unaffected by the interaction. Thus Region A connects to Region B, which connects to Region C. Regions L, M, and N, which also connect with each other, are never involved in the interaction between Regions A, B, and C. Ring-fenced interaction of this kind occurs not only in the visual system, but in more or less all the externally directed functional systems of the brain.

This type of interaction between neurons involves three main neurotransmitters. The principal excitatory neurotransmitters are glutamate and aspartate. The principal inhibitory neurotransmitter is GABA (gamma-aminobutyric acid). These are the most common neurotransmitters in the brain, and they dominate the activity of all channel functions.

The internally directed brain structures, units for modulating cortical tone and arousal, operate in an entirely different way. Here, the means of communication is more gross and involves widespread and global effects that reflect changes in the state of the organism rather than in specific information-processing channels. The neurons of single brain-stem nuclei in the state-dependent systems project onto extremely large numbers of other neurons in the source nuclei.

The forebrain neurons thus affected are extremely widely distributed within the brain, so that a nucleus in the brainstem can influence neurons in all lobes of the forebrain simultaneously. In addition, forebrain neurons affected by one state-dependent nucleus can simultaneously be influenced by another one; in these systems there are no specific pathways (channels) but, rather, a number of overlapping “fields of influence”.  The specific serial linkages between regions in the channel systems are replaced by overlapping and interacting fields. Even more characteristic of the state-dependent systems is the fact that they are also open to influence by chemicals other than neurotransmitters, which link the brain directly with the visceral body.

Brain's distinctions is similar to the distinction that Freud drew between mental “quality” and mental “quantity”. Illustration by Elena.

The Brain and the Inner World, Introduction to Basic Concepts. Mark Solms, Oliver Turnbull.

Cosmic Drama

The Fate of the Solar System

A supernova can be brighter than the combined radiance of all the other stars in the galaxy within which it is embedded.

Planets near stars much more massive than the Sun will be melted and frizzled by their sun when it becomes an erupting supernova, since these massive stars with higher temperatures and pressure run rapidly through their store of nuclear fuel, and their lifetimes are thus much shorter than the Sun’s.  In fact, a star tens of times more massive than the Sun can stably convert hydrogen to helium for only a short period of time – less than few millions years before moving on to more exotic nuclear reactions. All those massive blue-white supergiant stars in Orion are destined in the next few million years to become supernovae.

The essential preliminary to a supernova explosion is the generation of a massive iron core. Under enormous pressure, the free electrons in the stellar interior are melted with protons of the iron nuclei, the equal and opposite electrical charges canceling each other out;  the inside of the star is turned into a giant atomic nucleus, occupying a much smaller volume than the precursor electrons and iron nuclei.

A silicon fusion occurs and the core implodes violently, the exterior rebounds and a supernova explosion results.

On massive stars thus there is not enough time for the evolution of advanced forms of life on any accompanying planets. There will be not any beings there that could see their star become a supernova. Indeed, if intelligent beings live long enough to understand supernovae, their star is unlikely to become one.

The awesome supernovae explosion ejects into space most of the matter of the precursor star - residual hydrogen, helium, carbon, silicon, iron, uranium… Remaining is a core of hot neutrons, bound together by nuclear forces. This core is a single atomic nucleus with very heavy atomic weight. It becomes a neutron star thirty kilometers across: a rapidly rotating, tiny, shrunken, dense, withered stellar fragment. As the core of a massive red giant star collapses to form such a neutron star, it spins faster. The neutron star at the center of the Crab Nebula is an immense atomic nucleus, about the size of Manhattan, spinning thirty times a second. Its powerful magnetic field, amplified during the collapse, traps charges particles rather as the much tinier magnetic field emit beamed radiation not only at radio frequencies but in visible light as well. However, the fate of the inner solar system as the Sun becomes a red giant is grim enough.

Many stars in the Orion Constellation will become supernovae - a continuing cosmic fireworks in the constellation of the hunter. Image: © Megan Jorgensen.